Members of the trypsin/chymotrypsin-like (S1) serine protease family play pivotal roles in a multitude of diverse physiological processes, including digestive processes and regulatory amplification cascades through the proteolytic activation of inactive zymogen precursors. In many instances protease substrates within these cascades are themselves the inactive form, or zymogen, of a xe2x80x9cdownstreamxe2x80x9d serine protease. Well-known examples of serine protease-mediated regulation include blood coagulation, (Davie, et al (1991). Biochemistry 30:10363-70), kinin formation (Proud and Kaplan (1988). Ann Rev Immunol 6: 49-83) and the complement system (Reid and Porter (1981). Ann Rev Biochemistry 50:433-464). Although these proteolytic pathways have been known for sometime, it is likely that the discovery of novel serine protease genes and their products will enhance our understanding of regulation within these existing cascades, and lead to the elucidation of entirely novel protease networks.
Differentiated blood cells express an assortment of proteases that are likely to play specific roles in various pathological states. Although granzymes from cytotoxic T cells and natural killer (NK) cells (Smyth et al. (1996). J. Leukocyte Biol. 60:555-562), elastase and collagenases from neutrophils (Simon (1993). Agents Actions Suppl. 42:27-37) and chymase and tryptase from mast cells (Caughey (1995). Clin. Allergy Immunol. 6:305-29; Katunuma and Kido (1988). J. Cell. Biochem. 38:291-301) are currently under investigation, their roles in pathophysiological processes are only now being elucidated. In contrast, the proteases from eosinophils have not been characterized and are only currently being molecularly identified. Understanding the physiological roles these eosinophil proteases play will lead to a better understanding of eosinophil function in health and diseased states (Abu-Ghazaleh et al. (1992). Immunol. Ser. 57:137-67; Gleich (1996). Allergol. Int. 45:35-44; Gleich et al. (1993). Annu. Rev. Med. 44:85-101).
Proteases are used in non-natural environments for various commercial purposes including laundry detergents, food processing, fabric processing, and skin care products. In laundry detergents, the protease is employed to break down organic, poorly soluble compounds to more soluble forms that can be more easily dissolved in detergent and water. In this capacity the protease acts as a xe2x80x9cstain remover.xe2x80x9d Examples of food processing include tenderizing meats and producing cheese. Proteases are used in fabric processing, for example, to treat wool in order prevent fabric shrinkage. Proteases may be included in skin care products to remove scales on the skin surface that build up due to an imbalance in the rate of desquamation. Common proteases used in some of these applications are derived from prokaryotic or eukaryotic cells that are easily grown for industrial manufacture of their enzymes, for example a common species used is Bacillus as described in U.S. Pat. No. 5,217,878. Alternatively, U.S. Pat. No. 5,278,062 describes serine proteases isolated from a fungus, Tritirachium album, for use in laundry detergent compositions. Unfortunately use of some proteases is limited by their potential to cause allergic reactions in sensitive individuals or by reduced efficiency when used in a non-natural environment. It is anticipated that protease proteins derived from non-human sources would be more likely to induce an immune response in a sensitive individual. Because of these limitations, there is a need for alternative proteases that are less immunogenic to sensitive individuals and/or provides efficient proteolytic activity in a non-natural environment. The advent of recombinant technology allows expression of any species"" proteins in a host suitable for industrial manufacture.
Here we describe the molecular identification of a cDNA encoding a novel serine protease we have termed protease EOS. The protease EOS cDNA sequence predicts a preproEOS polypeptide of 284 amino acids, and its alignment with other well-characterized serine proteases clearly indicates that it is a member of the S1 serine protease family.
Enzymatically active protease EOS is amenable to further biochemical analyses for the identification of physiological substrates and specific modulators. Modulators identified in the chromogenic assay disclosed herein are potentially useful as therapeutic agents in the treatment of diseases associated with platelet function or elevated eosinophil counts such as in, but not limited to, bronchial asthma and complications arising from hypereosinophilia. In addition, expression of protease EOS in the ovary, retina and stomach suggests that modulators of protease EOS function could be used to treat disorders effecting these tissues. Purified protease EOS can be manufactured as a component for use in commercial products including laundry detergents, stain-removing solutions, and skin care products.
The recombinant DNA molecules coding for EOS, and portions thereof, are useful for isolating homologues of the DNA molecules, identifying and isolating genomic equivalents of the DNA molecules, and identifying, detecting or isolating mutant forms of the DNA molecules.